[PATCH 6.4 059/800] btrfs: fix file_offset for REQ_BTRFS_ONE_ORDERED bios that get split

Greg Kroah-Hartman
2023-07-16T19:56:52Z

From: Christoph Hellwig <hch@lst.de>

[ Upstream commit c731cd0b6d255e4855a7cac9f276864032ab2387 ]

If a bio gets split, it needs to have a proper file_offset for checksum
validation and repair to work properly.

Based on feedback from Josef, commit 852eee62d31a ("btrfs: allow
btrfs_submit_bio to split bios") skipped this adjustment for ONE_ORDERED
bios. But if we actually ever need to split a ONE_ORDERED read bio, this
will lead to a wrong file offset in the repair code. Right now the only
user of the file_offset is logging of an error message so this is mostly
harmless, but the wrong offset might be more problematic for additional
users in the future.

Fixes: 852eee62d31a ("btrfs: allow btrfs_submit_bio to split bios")
Reviewed-by: Johannes Thumshirn <johannes.thumshirn@wdc.com>
Reviewed-by: Josef Bacik <josef@toxicpanda.com>
Signed-off-by: Christoph Hellwig <hch@lst.de>
Reviewed-by: David Sterba <dsterba@suse.com>
Signed-off-by: David Sterba <dsterba@suse.com>
Signed-off-by: Sasha Levin <sashal@kernel.org>
---
fs/btrfs/bio.c | 3 +--
1 file changed, 1 insertion(+), 2 deletions(-)

diff --git a/fs/btrfs/bio.c b/fs/btrfs/bio.c
index b3ad0f51e6162..b86faf8126e77 100644
--- a/fs/btrfs/bio.c
+++ b/fs/btrfs/bio.c
@@ -95,8 +95,7 @@ static struct btrfs_bio *btrfs_split_bio(struct btrfs_fs_info *fs_info,
btrfs_bio_init(bbio, fs_info, NULL, orig_bbio);
bbio->inode = orig_bbio->inode;
bbio->file_offset = orig_bbio->file_offset;
- if (!(orig_bbio->bio.bi_opf & REQ_BTRFS_ONE_ORDERED))
- orig_bbio->file_offset += map_length;
+ orig_bbio->file_offset += map_length;

atomic_inc(&orig_bbio->pending_ios);
return bbio;
--
2.39.2